Directional control and discharge enhancement of SDBD plasma via dynamic scanning magnetic fields

Here, we propose a dynamic scanning magnetic field (DSMF) scheme for atmospheric-pressure surface dielectric barrier discharge (SDBD) plasmas, realized by sequentially commutated coils as a compact alternative to bulky static magnets. The DSMF simultaneously lowers the breakdown threshold and enables half-cycle directional control of discharge current through induction-assisted electric fields. Combined experiments and simulations reveal that the induced field and E×B drift enhance electron temperature and density by factors of ~1.8 and ~1.4 at 0.35 T and 200 Hz, surpassing the performance of static full-field configurations under the present operating conditions. This dynamic modulation significantly improves discharge uniformity, introduces tunable asymmetry, and promotes the generation and transfer of long-lived reactive oxygen and nitrogen species (RONS). Consequently, aqueous H2O2, NO2⁻/NO3⁻, and O3 concentrations are markedly increased, leading to a 23.7% improvement in methyl orange degradation efficiency and a fourfold enhancement in energy yield compared with static full-field case. These results establish DSMF as an effective and scalable strategy for magnetic-field control of non-equilibrium plasmas, with broad implications for plasma-based chemical processing and environmental applications.